Surgical Access Instruments For Use With Delicate Tissues

ABSTRACT

Surgical instruments providing access to delicate tissue, such as brain tissue or breast tissue, through a transcutaneous incision. A surgical apparatus may have a hollow sleeve retractor extending along a longitudinal axis from a proximal retractor end to a distal retractor end and an introducer having a proximal introducer end and a distal introducer end. The proximal introducer end is configured to install within the hollow sleeve with its distal end extending beyond the distal retractor end. The distal introducer end is tapered and may have a rounded profile in a plane parallel to the longitudinal axis to displace delicate brain tissue transversely to the longitudinal axis without damage to the tissue. The distal retractor end may be blunt and adapted to support adjacent brain tissue while minimizing disruption to the tissue after the retractor is positioned at a surgery site and the introducer is removed from the retractor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/155,175 filed Jun. 17, 2005, which application is incorporated hereinby reference in its entirety.

FIELD OF INVENTION

This disclosure relates to surgical access instruments for use withdelicate tissues and methods of use.

BACKGROUND

Traditional surgical brain retractors are thin, firm or malleable bandsof steel or other metal alloys, with abrupt or well-defined edges andhave limited surface areas. The common structural form of the standardretractor is a simple strip of metal consisting of a metal strip whichcan be bent by hand and the surface of which typically is used to pullapart or spread delicate tissue. The strip typically is clearly outlinedon the brain after a few minutes, and particularly noticeable are thepressure marks from the lateral spatula edges which indicate a highlocal compression stress. These traditional retractors can be introducedinto the tissue of the brain or along brain surfaces, and then pulledwith force to either separate or elevate the brain tissue duringsurgery. This method allows the target area to be illuminated andvisualized in order to perform the surgical procedure. However, braintissue is quite soft and delicate, particularly after trauma, loss ofblood supply, or in the presence of brain edema. The brain tissue is agel-like substance that can be easily damaged, and a complication knownas “retraction injury” can occur, sometimes resulting in compromisedbrain function. The brain tissues can be torn by the relatively sharpedges of these retractors, and/or the retracted brain can lose bloodsupply when the local pressure beneath the retractor is greater thanvenous pressure. The result can be ischemic changes in the underlyingbrain and/or the more serious complication of venous brain infarction.

The combination factors including the softness of the brain tissue, andthe effects of sharp, blunt edges and limited surface area oftraditional metal band retractor also results in limited visualizationof the surgical target area. The brain tends to extend beyond or “droop”around the edges of the retractor, limiting the area necessary forlighting and reducing overall visibility.

Furthermore, the amount of local pressure exerted by the retractor onthe brain tissue must be limited to avoid injury, which may impede thesurgeon's ability to safely gain enough visualization area. Oftentimes,the surgeon will resort to the strategy of exposing far more of thebrain tissue than is necessary or desirable to open the area around thebrain widely enough so as to limit the amount of local retractionpressure. This method is undesirable, as compared to a less invasiveapproach, for both the patient and surgeon.

It would be advantageous to provide a surgical instrument assembly thatsafely addresses the shortcomings of the presently-known instruments.

EXEMPLARY OBJECTS OF THE INVENTION

Exemplary objects and design principles of the surgical accessinstrument assemblies of this invention are as follows:

-   (1) to maximize surface area of the retractor, so as to distribute    pressure evenly and minimize effective local retraction pressure or    specific high pressure points;-   (2) to enable integration with stereotactic neuro-navigation    computer guidance system;-   (3) to reduce the need to “pull” on a brain retractor, to obviate    the possibility of accidental over-retraction and thereby avoid    brain damage;-   (4) to allow for binocular vision with the utilization of elliptical    architecture;-   (5) to allow for maximal lighting access clearance and target tissue    visualization;-   (6) to allow for minimization of brain disruption by limiting the    corticotomy via use of a small elliptical window for the    transcortical introducer;-   (7) to allow for minimization of brain disruption with the    utilization of tapered forward edges;-   (8) to enable stable retraction fixation to avoid accidental    retractor displacement;-   (9) to provide retractors which are of lightweight materials to    allow for ease of manipulation; and/or,-   (10) to provide transparent retractors to allow for direct    visualization of underlying brain tissue.

Other objects also may become apparent from the following description ofthe present invention.

SUMMARY OF THE INVENTION

In keeping with these objects and others which may become apparent, thepresent invention is directed toward an access assembly for surgicalinstruments. Non-limiting, exemplary embodiments of the access assemblyare described in this Summary of the Invention and elsewhere herein. Theaccess assembly for surgical instruments includes two principalcomponents. One component is an internal instrument access assembly andthe other is an external instrument access assembly. The internalinstrument access assembly is designed to enter the brain to gain accessto deeper internal brain structures. The external instrument accessassembly is designed to separate or elevate the surfaces of the brain togain access to external structures along, around or beneath the brain.Both will be produced in varying sizes according to the needs ofindividual operations. The materials for these retractors will becomposed of transparent biocompatible lightweight plastic. Each of theinstrument assemblies includes two separate parts: a retractor that alsofunctions as a working channel, and a compatible introducer.

The internal instrument assembly is a wedge retractor introducer, whichpreferably includes a hollow wedge formed by all or part of a closedcurve in cross section, such as an elliptical rounded wedge or an archshaped wedge. It includes a hollow brain access working channel that canbe fixed in space to a standard neurosurgical fixation cable device.First, a protruding introducer element, having a length greater than thelength of the hollow working channel, is introduced into the workingchannel. Its distal smooth and relatively soft tapered end works tospread apart the brain hemispheres or other portions of delicate braintissue. When the working channel is introduced, the introducer isremoved, leaving the hollow working channel for the surgeon to access tothe target tissues. Variations will include length (Z axis), and widthand height (X and Y axes) of the elliptical working channel andintroducer.

A fixation portion is designed to be attached to a standardneurosurgical armature fixation device.

The external surgical access instrument assembly is characterized by anarched hemi-elliptical architecture, wider along the base (X axis) thantall (Y axis). It is smooth, tapered at the leading edge, has a handlefixation portion that is o the same design as that of the internalinstrument assembly, and is designed to be attached to a standardneurosurgical armature fixation device. Variations will be in length (Zaxis) as well in X and Y axes.

Therefore, the present invention encompasses one or more surgicalinstrument assemblies to provide access to delicate tissue at the end ofthe working channel, such as brain tissue or breast tissue, through atranscutaneous incision, for a variety of reasons, such as to access asurgical site; to provide access to insert an inflatable prosthesis; orto provide access for providing an external buttress channel forsupporting tissue thereon. The surgical instrument assembly includes aninterleaved combination of an open sleeve hollow retractor and a taperedtipped wedge introducer. The wedge introducer is introduced into an areaadjacent to the hollow sleeve. The distal tip of the wedge introducerextends beyond a distal end of the hollow retractor, forward of a distalend of said hollow retractor, so that the wedge introducer traverses thedelicate tissue ahead of the distal end of the hollow retractor, guidingthe hollow retractor into place in the delicate tissue.

When used in conjunction with working surgical instruments, the distalend of the introducer has a small opening, preferably elliptically oval,to allow for removal of small portions of tissue from a surgical site.

The hollow retractor may have a diameter which is a closed curve, suchas an elliptical oval. In such case, a tapered tipped wedge introduceris inserted into the inside of the closed curved hollow retractor. In analternate embodiment, the tapered tipped wedge introducer may have adiameter which is an arc, wherein the arc is a portion of a closedcurve, and further wherein the tapered tipped wedge is an archinsertable into the closed curved hollow retractor.

When used as an external working channel, the distal end of the workingchannel is bell shaped, to allow for increase for increased surface areaexposure.

The hollow retractor may alternatively also be an arc of a portion of aclosed curve, also forming an arch shape. In such case, the taperedcurved tipped wedge introducer may also be an arc of a portion of aclosed curve, also forming an arch shape.

In the case where the hollow retractor and/or the tapered tipped wedgeintroducer has a diameter of at least one arc of a curve, theypreferably can have a decreasing curved cross sectional diameter.

Moreover, in such case where the hollow retractor is arch shaped, asopposed to being a closed curved shape, such as being an-elliptical ovalin cross section, the wedge introducer is placed adjacent to the concaveinner portion of the hollow retractor.

If the hollow retractor is a closed curve, that is, having an ellipticaloval cross section, preferably of decreasing diameter towards it distal,tissue contact edge, then the combination of the hollow retractor andwedge introducer are used to either spread apart adjacent delicatetissues, such as the left and right hemispheres of the brain, or totraverse the delicate tissue, such as brain tissue, to provide internalaccess to a surgical site within the delicate tissue.

If the hollow retractor is arch-shaped, that is, having a diameter whichis an arc, namely, a portion of a closed curve, then the combination ofthe hollow retractor and the wedge introducer are used to provide accessto a delicate tissue, where the delicate tissue is supported upon theconvex outer surface of the hollow retractor, forming a supportbuttress, after removal of the arch-shaped wedge introducer.

Additionally, if the hollow retractor is also arch-shaped, that is,having a diameter which is an arc, namely, a portion of a closed curve,then additionally the combination of the hollow retractor and the wedgeintroducer is used to provide access to a delicate tissue, where aninflatable member, such as a breast prosthesis, is inserted into thedelicate breast tissue and inflated, after removal of the arch-shapedwedge introducer from the hollow arched retractor.

The tipped wedge introducer has an exterior surface corresponding to aninterior Surface of the hollow sleeve and the closed end tipped wedgeintroducer may have a diameter with an arc of a decreasing curved crosssection approximating the arc of the curved cross section of the opensleeve of the retractor.

Preferably, the retractor includes a handle or a tab that is attachableto a clamp.

Optionally, the hollow retractor and the tapered tipped wedge introducerinclude a lock temporarily locking said tapered tipped wedge introduceradjacent to the hollow retractor.

When the hollow retractor is elliptically oval in cross section, theclosed plane curve is generated by a point moving in such a way that thesums of its distances from two fixed points is a constant, or the closedplane curve is a plane section of a circular cone that is a notperpendicular to an axis of the cone, thereby forming a planarelliptical oval slice through the cone.

Moreover, the hollow retractor may be flared at a proximal end.Additionally, where a base of a handle is attached, the handle may mergein a cascading shape, interrupting the continuous curve of the proximalend of the hollow retractor. Such a cascading dip in structure allowsfor easier finger access into the working channel of the hollowretractor.

Additionally, the hollow retractor may have a changing cross section,where the cross sectional diameter of the elliptical oval is wider ornarrower at selected regions of the working channel of the hollowretractor.

DESCRIPTION OF THE DRAWINGS

The present invention can best be understood in connection with theaccompanying drawings. It is noted that the invention is not limited tothe precise embodiments shown in drawings, in which:

FIG. 1 is a view of a patient with a retractor assembly and a buttresschannel positioned adjacent to a top of the head and lower skull.

FIG. 2 is a perspective of retractor assembly of FIG. 1.

FIG. 3 shows exploded components of FIG. 2.

FIG. 4 is a top plan view of an introducer.

FIG. 5 is a proximal end view of an introducer.

FIG. 6 is a side sectional elevational view thereof.

FIG. 7 is a top plan sectional view thereof.

FIG. 8 is a sectional detail of a locking tab, taken from FIG. 7.

FIG. 9 is a top plan view thereof.

FIG. 10 is a proximal end view of the retractor.

FIG. 11 is a side sectional elevation thereof.

FIG. 12 is a top plan sectional view thereof.

FIG. 13 is a sectional detail view of the groove, taken from FIG. 12.

FIG. 14 is a sectional detail of locking tab and groove, taken at 14-14of FIG. 2.

FIG. 15 is a proximal end view of the assembly, taken at arrow 15 inFIG. 2.

FIG. 16 is a view of the instrument assembly being inserted into the topof a skull.

FIG. 17 is a view of the instrument assembly spreading the brain lobesapart.

FIG. 18 is a view of the instrument assembly installed, taken at arrows18-18 of FIG. 17, with an ear of introducer flexed.

FIG. 19 is a view of the instrument assembly with the introducerremoved.

FIG. 20 is a view of surgical instruments within the retractor channel.

FIG. 21 is a diagrammatic sectional view of an embodiment which isinstalled transversely into tissue.

FIG. 22 is a view of the external instrument assembly system adjacent tothe lower skull.

FIG. 23 is a view of the instrument assembly components of FIG. 22exploded.

FIG. 24 is a perspective view of the instrument assembly systeminstalled in the lower skull.

FIG. 25 is a diagrammatic side section of installed instrument assembly,with the introducer removed.

FIG. 26 is a diagrammatic view of the instruments working on an externaltumor.

FIG. 27 is a diagrammatic view of an alternative embodiment, installedthrough forehead.

FIG. 28 is a diagrammatic view of the instrument assembly installed intobreast tissue.

FIG. 29 is a perspective exploded view of a surgical kit.

DETAILED DESCRIPTION

This disclosure relates to a surgical instrument assembly and system foruse with delicate tissues and methods of using the instrument assembly.The instruments are designed for use during surgery on delicate tissues,such as brain and breast tissues, although they may be used in anymedical context. The instrument assembly includes several portions, suchas, an introducer portion, a tissue access channel retractor portion(“channel portion”) having at least one handle portion, and a styletteportion. These instrument portions are formed to maximize the surfacearea of the retractor, which distributes pressure approximately equallythough out the surrounding tissues and minimizes effective localizedretraction pressure on the tissues in contact or immediately surroundingthe instrument.

In one embodiment, the surgical instrument assembly can be a retractorin the form of an arch or arc shape, into which an arch or arc shapedwedge introducer may be inserted for surgical access to the externalportions or surfaces of the brain.

In another embodiment, the surgical instrument assembly can be aretractor in the form of a wedge with a tapered elliptical crosssectional shape, into which a tapered elliptical cross sectionalintroducer may be inserted for surgical access to the external portionsor surfaces of the brain.

Alternatively, the external retractor and wedge introducer may be usedto insert medical/cosmetic devices into or under delicate tissues.

The surgical instrument assembly system may also employ the externalretractor as an external brain support buttress channel portion to liftthe brain mass upward with respect to the cranium to provide stabilityand prevent the gelatinous brain materials from shifting during surgery.In the capacity of a brain support buttress channel portion (“buttressportion”) also provides improved visualization and improved access tothe surgical area by lifting the brain matter upward in the cranium.

The formation of the instrument assembly also eliminates the need to“pull” a retractor against tissue to clearly visualize the surgical areaby initially providing a sufficient work area via the channel retractor.The use of the tissue access channel retractor portion of the instrumentassembly eliminates or greatly lowers the possibility of accidentalover-retraction. By avoiding excess retraction, damage to thesurrounding tissues is also avoided, including possible brain damage.

While other closed curve configurations may be used, the preferablyelliptical or arch shaped architecture formation of the instrumentassembly portions is such that medical staff is afforded binocularvision, rather than the monocular vision typically found in similardevices. This elliptical architecture also provides far greaterclearance for lighting access to illuminate the target surgical area andallows full visualization of that area. The forward edge of the channelretractor is preferably tapered to gently separate tissue to obtain asurgical area and minimizes disruption of the tissue.

The surgical instrument assembly system may also be useful as aninserter instrument for breast implants.

The dimensions of the surgical instrument assembly may vary and bemodified according to an intended use. Generally, the surgical workspace formed by the introducer portion 40 can have diameters of in therange of approximately 10 millimeters (“mm”) to approximately 100 mm,and more typically in the range of approximately 25 mm to approximately75 mm in its closed configuration. The open configuration of theintroducer portion 40 may extend the diameter of the distal end 42 ofthe introducer portion 40 several millimeters, and may generally bedetermined by amount of extension desired by the surgical team duringuse as it is introduced into the lumen 22 of the retractor 20, and mayinclude a flexible band portion 14 to enhance its flexibility. The openconfiguration may also be determined by the overall desiredcircumference and diameter of the surgical instrument assembly for aparticular use and may be manufactured in a variety of useful sizes tobe available as is practical. The Surgical instrument assembly may beformed of any biocompatible material which will provide sufficientstability and strength necessary to provide a surgical work area. Thebiocompatible material may be disposable or sterilize-able for repeateduse. In one embodiment, the surgical instrument assembly may be formedof a lightweight plastic material for ease of manipulation and/or thematerial may be transparent to allow direct visualization of underlyingbrain tissue thorough the instrument assembly portions.

The surgical instrument assembly system also enables integration withstereotactic neuro-navigation computer guidance systems to enhancevisualization of the surgical area of the brain.

FIG. 1 illustrates in diagrammatic fashion the surgical instrumentassembly system 10 adjacent a surgical aperture in the cranium of anintubated patient. An external retractor system 100 is also spaced fromthe lower skull, and will be described later in the specification.

FIG. 2 is an enlarged perspective view of the surgical instrumentassembly system 10 as shown in FIG. 1. The instrument assembly system 10is comprised of two components, a retractor 20, and an introducer 40.

FIG. 3 illustrates the relationship of introducer 40 to retractor 20,prior to assembly. It is desirable that the introducer is easily fixedto and removable from the retractor both prior to and during thesurgical procedure.

As also shown in FIG. 3, the surgical instrument assembly system may beformed by any method, including injection molding, as a single piece, ormay be formed of two or more pieces which are permanently fixedlyattached to each other. The distal end 42 of the introducer portion 40is preferably a solid, rounded cone shape which may or may not includean opening 52 to the surrounding tissues as opposed to a cannulastructure which always provides a distal opening. The distal end 42preferably includes a gently increasing circumference 54, whichincreases and expands towards the proximal end 56 of the introducerportion 42. The introducer portion 40 has a main body 50, and may bedivided into two approximate handle halves 46, having V-shaped cutouts48 between the handle halves. The halves of the proximal end 56 are anintegral unit, the term “halves” is used as a descriptor only and doesnot describe separable parts, as opposed to two disassemblable halves.The proximal end 56 may include at least one handle portion 46 whichextends outwardly at an angle of approximately 90 degrees. A handleportion 46 may be useful to allow a medical team member to physicallyinsert, manipulate or hold the handle portion 46, or a conventionalsurgical fixation cable may be attached to the handle portion 12. Atleast one of the handle portions 46 include at least one indentation orgroove 44 to accept or snap into an additional portion of the surgicalinstrument assembly 10.

FIGS. 4-8 show a variety of views of the retractor portion 20 of thisdisclosure, including retractor 20 having a hollow working channel 22and handle 28. The retractor 20 is generally formed to dimensions andshapes to coincide with the introducer portion 40 that may be slideablyinserted into the brain access work channel 22 of the retractor portion20. The retractor portion 20 is generally shorter in length than theintroducer portion 40 to allow the distal end 42 of the introducerportion 40 to interact with the surrounding housing 21 tissues. As bestseen in FIGS. 6 and 7, the retractor portion 20 is formed as a hollowelliptical rounded wedge having a tapered distal leading edge 24. Theproximal edge of the retractor 20 includes a slightly rounded lip 26 anda handle portion 28. At least one tab 30 is formed in wedge 21, justdistal of lip 26. Tab 30 will positively align with groove 44 ofintroducer 40 to prevent or inhibit unnecessary movement or slipping ofthe instrument assembly components best seen in sectional view FIG. 15.The handle portion 28 allows the retractor portion 20 to be fixed inspace with the use of a standard or conventional neurosurgical fixationcable device.

FIG. 9 illustrates a side view of a retractor 20, having a proximal end26 of the surgical instrument assembly and optionally having a handleportion 28 perpendicular to the proximal end 26; and an ellipticallength of the retractor 21 extends to the rounded distal end 24. FIG. 10is a frontal view of the retractor 20, showing the lumen 30 and thehandle portion 28. FIG. 11 is a cross-sectional view of the retractor 20of the rounded shape of the retractor 20 to avoid damage to delicatetissues. FIG. 12 is a top plan view of the retractor 20, emphasizing thegroove like cut-out hole 30 which can allow the introducer 40 tointegrally fit and temporarily lock/snap into hole 30, thereby causingboth the retractor 20 and introducer 50 to function as one, whiledesired by the medical team. FIG. 13 is an enlarged view of the groovedhole 30. FIG. 14 is a cross-sectional view of the tab 44 of theintroducer 20 while it is engaged within the grooved hole 30 of theretractor 20.

Shown in FIG. 15 is a proximal end view of assembled instrument wherethe handle portions 46 overlying lip 26 of retractor 20, and V-shapedcutouts 48 residing in lumen 22. Handle 28 of retractor 20 is moldedintegral with lip 26, providing both rigidity and strength. FIG. 15 alsoshows that where a base of handle 28 is attached to retractor 20, handle28 may optionally merge in a cascading shaped dip 28 a, interrupting thecontinuous curve of the proximal end of hollow retractor 20. Such acascading dip 28 a allows for easier finger access into the workingchannel of hollow retractor 20.

FIGS. 16-20 illustrate diagrammatically the method if installingsurgical instrument assembly 10 into the aperture 12 in cranium 14. Asseen in FIG. 16, instrument assembly IO is inserted into aperture 12.Distal end 42 of introducer 40 is abutting brain tissue 60. Asinstrument assembly 10 is introduced, distal end 42 of introducer 40begins to spread tissue or lobes 62 and 64 of brain 60, as shown in FIG.17. FIG. 18 is an elevational view of the installed surgical instrumentassembly 10, taken along arrows 18-18 of FIG. 17. Upon installation,handles 46 of introducer 40 may be flexed inward. thereby releasing thetab 30 of retractor 20 from the groove 44 of introducer 40. FIG. 19illustrates introducer 40 during removal from lumen 22 of retractor 20.FIG. 20 shows surgical instruments 70 within lumen 22 of retractor 20,examining brain tissue 60.

FIG. 21 is a diagrammatic perspective view of an embodiment of thesurgical instrument assembly 10, adjacent an aperture 12 located at thetemple region of a patient's cranium 14. In this embodiment, the overalllength of surgical instrument assembly 10 is sufficient to transverselypenetrate the cranium and brain tissue 60. Surgical instrument assembly10 is shown installed in FIG. 22.

FIG. 23 is a perspective view of the external retracting buttresschannel 100. External buttress channel instrument assembly 100 iscomprised of buttress channel component 200, and wedge introducercomponent 400. External buttress channel component 200 has a generallyarched, hemi-elliptical architecture, where it is wider along the basethan it is tall or high. The buttress channel component 200 includes asmooth, tapered leading edge 202. A handle fixation member 204 isapproximately perpendicular to the rounded lip 206 of the proximal end208. The handle member 204 may be employed as an attachment point to astandard neurosurgical armature fixation device. The external buttresschannel component 200 may be used to lift, support or manipulate thebrain within the skull cavity to provide additional or improved visionof the surgical area, as seen in FIG. 24.

Also seen in FIG. 23 is the external wedge introducer portion 400 forthe external buttress channel component 200. Buttress channel 200 isdesigned to gain access to external structures along, around or beneaththe brain by elevating the surfaces of the brain to allow access tosurgical locations on or near the surface of the brain tissues. Inoperation, prior to insertion, introducer portion 400 is attached tobuttress channel 200 such that sloping distal end 402 protrudes from thedistal open end 210 of buttress channel 200. This pushes away braintissue at the outer brain surface 66 gently during insertion. Afterinsertion, introducer portion 400 is withdrawn to leave a workingchannel of decreasing hemi-oval cross section from proximal end 208 todistal end 210. Radial surface of buttress channel 200 supports theouter surface 66 of the brain tissue 60, best seen in FIG. 24. Note thatsurface of wedge introducer 400 conforms to the inside of buttresschannel surface; proximal end 208 and handle member 204 conform toproximal end 406 and fixation member 408 of introducer 400 respectively.Fixation member 204 of buttress channel 200 is designed to be attachedto a standard neurosurgical armature fixation device.

FIGS. 25 and 26 are diagrammatic view of the instruments working on anexternal tumor, where the further surgical instruments 70 are insertinginto the operating space formed by the instrument assembly system toallow the surgical team to work on the tissues as necessary.

FIG. 27 is a diagrammatic view of an embodiment, which may be installedthrough the forehead as necessary for surgical procedures. FIG. 28 is adiagrammatic view of the instrument assembly installed into breasttissue 68, where it may be used for insertion of implants 72 and thelike.

FIG. 28 shows use of an arched buttress channel 200 and wedge introducercomponent 400 which may be used, for example, for access to brain tissueor for inserting an inflatable prosthesis into breast tissue.

FIG. 29 is a perspective exploded view of a surgical kit. The Kit 600includes an injection-molded or vacuum-formed housing 602, providingcavities 604 to receive components of the surgical instrument assemblysystem 10 and the external retracting buttress channel system 100. Astylette 80 may also be included. Upon placement of all desiredcomponents within the housing 602, the sterile kit will be sealed with aTyvek sheet 606. Upon removal of sheet 606 by the surgeon, the sterilecomponents of kit 600 can be utilized and employed as required in asurgical operation.

In the foregoing description, certain terms and visual depictions areused to illustrate the preferred embodiment. However, no unnecessarylimitations are to be construed by the terms used or illustrationsdepicted, beyond what is shown in the prior art, since the terms andillustrations are exemplary only, and are not meant to limit the scopeof the present invention.

It is further known that other modifications may be made to the presentinvention, without departing the scope of the invention, as noted in theappended Claims.

1. A surgical apparatus comprising: a retractor having a hollow sleeveextending along a longitudinal axis from a proximal retractor end to adistal retractor end; and an introducer having a proximal introducer endand a distal introducer end, the proximal introducer end beingconfigured to selectively install within the hollow sleeve with thedistal introducer end extending beyond the distal retractor end, whereinthe distal introducer end is tapered to generally reduce in size from alocation adjacent the distal retractor end to the distal retractor end,and wherein the distal introducer end has a rounded profile in a planeparallel to the longitudinal axis to displace delicate tissuetransversely to the longitudinal axis without damage to the delicatetissue.
 2. The surgical apparatus of claim 1, wherein: the hollow sleevecomprises an enclosed channel; and the cross-sectional shape, withrespect to a plane perpendicular to the longitudinal axis, of at least aportion of the enclosed channel is elliptical, round, or oval.
 3. Thesurgical apparatus of claim 1, wherein at least a portion of the hollowsleeve comprises an open channel having a generally arched shape.
 4. Thesurgical apparatus of claim 1, wherein the hollow sleeve is tapered,along at least a portion of its length, to have a larger size at theproximal retractor end and a smaller size at the distal retractor end.5. The surgical apparatus of claim 1, wherein the distal retractor endis rounded.
 6. The surgical apparatus of claim 1, wherein the distalretractor end is shaped to generally correspond to the shape of an outersurface of the introducer located adjacent and outside the distalretractor end when the introducer is selectively installed within theretractor.
 7. The surgical apparatus of claim 1, wherein the proximalretractor end comprises a cascading dip located at a portion of aperimeter of the hollow sleeve.
 8. The surgical apparatus of claim 1,wherein the distal introducer end comprises a rounded cone.
 9. Thesurgical apparatus of claim 8, wherein the distal introducer endcomprises an opening therethrough.
 10. The surgical apparatus of claim1, wherein the retractor comprises a handle connected to the hollowsleeve with sufficient rigidity to fix the hollow sleeve in space withrespect to a patient's delicate tissue when attached to a surgicalclamp.
 11. The surgical apparatus of claim 1, wherein the hollow sleevecomprises a transparent material.
 12. The surgical apparatus of claim 1,wherein the hollow sleeve is dimensioned to permit simultaneous accessfor a plurality of surgical instruments to a surgical site adjacent thedistal retractor end when the introducer is removed from the retractor.13. The surgical apparatus of claim 1, wherein the distal retractor endforms a surgical work space having a diameter about 10 millimeters toabout 100 millimeters.
 14. The surgical apparatus of claim 1, whereinthe distal retractor end forms a surgical work space having a diameterabout 25 millimeters to about 75 millimeters.
 15. The surgical apparatusof claim 1, wherein the delicate tissue comprises brain tissue.
 16. Thesurgical apparatus of claim 1, wherein the introducer and the retractorhave corresponding locking features adapted to temporarily secure theintroducer to the retractor.
 17. The surgical apparatus of claim 16,wherein the locking features comprise one or more protrusions formed onan exterior surface of the introducer and one or more correspondingdetents formed on an interior surface of the retractor, the one or moreprotrusions being engaged with the one or more detents when theintroducer is fully inserted in the retractor.
 18. The surgicalapparatus of claim 17, wherein the proximal introducer end comprises oneor more cutouts dividing the proximal introducer end into first andsecond handles that are movable with respect to one another, and the oneor more protrusions comprise a first protrusion located on the firsthandle and a second protrusion located on the second handle.
 19. Asurgical apparatus comprising: a retractor having a hollow sleeveextending along a longitudinal axis from a proximal retractor end to adistal retractor end; and an introducer having a proximal introducer endand a distal introducer end, the proximal introducer end beingconfigured to selectively install within the hollow sleeve with thedistal introducer end extending beyond the distal retractor end, whereinthe distal introducer end is tapered to generally reduce in size from alocation adjacent the distal retractor end to the distal retractor end,and wherein the distal introducer end comprises means for displacingdelicate tissue transversely to the longitudinal axis without damage tothe delicate tissue as the introducer is moved along the longitudinalaxis to a surgery site.
 20. The surgical apparatus of claim 19, whereinthe distal introducer end has a rounded profile in a plane parallel tothe longitudinal axis.
 21. The surgical apparatus of claim 19, whereinthe distal introducer end comprises a rounded cone.
 22. The surgicalapparatus of claim 19, wherein the distal introducer end comprises anopening therethrough.
 23. The surgical apparatus of claim 19, whereinthe delicate tissue comprises brain tissue.
 24. A surgical apparatuscomprising: a retractor having a hollow sleeve extending along alongitudinal axis from a proximal retractor end to a distal retractorend; and an introducer having a proximal introducer end and a distalintroducer end, the proximal introducer end being configured toselectively install within the hollow sleeve with the distal introducerend extending beyond the distal retractor end, wherein the distalintroducer end is blunt and is tapered to generally reduce in size froma location adjacent the distal retractor end to the distal retractorend; wherein the distal retractor end is blunt and adapted to supportadjacent delicate tissue while minimizing disruption to the delicatetissue after the retractor is positioned at a surgery site and theintroducer is removed from the retractor.
 25. The surgical apparatus ofclaim 24, wherein the hollow sleeve comprises an enclosed channel. 26.The surgical apparatus of claim 24, wherein at least a portion of thehollow sleeve comprises an open channel.
 27. The surgical apparatus ofclaim 24, wherein the hollow sleeve is tapered, along at least a portionof its length, to have a larger size at the proximal retractor end and asmaller size at the distal retractor end.
 28. The surgical apparatus ofclaim 24, wherein the distal retractor end is rounded.
 29. The surgicalapparatus of claim 24, wherein the distal retractor end is shaped togenerally correspond to the shape of an outer surface of the introducerlocated adjacent and outside the distal retractor end when theintroducer is selectively installed within the retractor.
 30. Thesurgical apparatus of claim 24, wherein the proximal retractor endcomprises a cascading dip located at a portion of a perimeter of thehollow sleeve.
 31. The surgical apparatus of claim 24, wherein thedistal introducer end has a rounded profile in a plane parallel to thelongitudinal axis.
 32. The surgical apparatus of claim 24, wherein thedistal introducer end comprises a rounded cone.
 33. The surgicalapparatus of claim 24, wherein the retractor comprises a handleconnected to the hollow sleeve with sufficient rigidity to fix thehollow sleeve in space with respect to a patient's delicate tissue whenattached to a surgical clamp.
 34. The surgical apparatus of claim 24,wherein the hollow sleeve comprises a transparent material.
 35. Thesurgical apparatus of claim 24, wherein the hollow sleeve is dimensionedto permit simultaneous access for a plurality of surgical instruments toa surgical site adjacent the distal retractor end when the introducer isremoved from the retractor.
 36. The surgical apparatus of claim 24,wherein the distal retractor end forms a surgical work space having adiameter about 10 millimeters to about 100 millimeters.
 37. The surgicalapparatus of claim 24, wherein the distal retractor end forms a surgicalwork space having a diameter about 25 millimeters to about 75millimeters.
 38. The surgical apparatus of claim 24, wherein thedelicate tissue comprises brain tissue.
 39. The surgical apparatus ofclaim 24, wherein the introducer and the retractor have correspondinglocking features adapted to temporarily secure the introducer to theretractor.
 40. A surgical apparatus comprising: a retractor having ahollow sleeve extending along a longitudinal axis from a proximalretractor end to a distal retractor end; and an introducer having aproximal introducer end and a distal introducer end, the proximalintroducer end being configured to selectively install within the hollowsleeve with the distal introducer end extending beyond the distalretractor end, wherein the distal introducer end is blunt and is taperedto generally reduce in size from a location adjacent the distalretractor end to the distal retractor end; wherein the distal retractorend comprises means for supporting adjacent delicate tissue whileminimizing disruption to the delicate tissue after the retractor ispositioned at a surgery site and the introducer is removed from theretractor.
 41. The surgical apparatus of claim 40, wherein the distalretractor end is rounded.
 42. The surgical apparatus of claim 40,wherein the distal retractor end is shaped to generally correspond tothe shape of an outer surface of the introducer located adjacent andoutside the distal retractor end when the introducer is selectivelyinstalled within the retractor.
 43. The surgical apparatus of claim 40,wherein the delicate tissue comprises brain tissue.